1. Field of the Invention
The present invention relates generally to a vehicle room floor illuminating apparatus, and more specifically to a vehicle room floor illuminating apparatus for illuminating only the vehicle room floor of a passenger car, for instance.
2. Description of the Prior Art
In the conventional automotive vehicles, since the vehicle room is illuminated by only a room lamp attached to ceiling of the vehicle room, the illumination light is not broadly transmitted to all of the vehicle room floor or to all of the corners within the vehicle room, because the illumination light is intercepted by vehicle seats or passengers. Therefore, there exists a problem in that the space near passenger's feet is usually dark, and, therefore, the passenger feels that the vehicle room space is narrower than it is.
The above-mentioned problems can be explained as follows: First, when the vehicle room is dark near the passenger's feet, the passenger's eyes naturally see the brightest position near their eyes (e.g. the room light), so that the passenger feels that the vehicle room is narrow. Secondly, when the vehicle is running along a bright street, since the passenger's eyes are adapted to the external bright environment (light adaptation) and therefore the eyes' sensitivity decrease, the passenger feels the position near the passenger's feet to be darker than it is. Thirdly, when the vehicle room is illuminated directly by another room lamp, since shadows of the seats or the passengers are inevitably produced on a vehicle room floor, the vehicle room floor will not be illuminated broadly and uniformly.
In the conventional vehicle room illuminating apparatus, as described above, there exist problems in that the passenger feels the vehicle room floor to be dark and therefore the vehicle room space to be narrower, and also feels uneasy. Additionally, a passenger cannot easily pick up an object on the room floor.
The further detail of the above-mentioned problems in connection with illumination and illumination method under due consideration of human eyes is described in "LIGHTING HANDBOOK", edited by ILLUMINATING ENGINEERING INSTITUTE OF JAPAN, which is incorporated herein by reference.